NAV 5.0 SP1: Changing Item Tracking Code for Item with Ledger Entries (CK-NAV 14-JAN-2010)

We have a new request. We are considering to change the Item Tracking Method to allow us to do both Lot No. and Serial No. tracking for Items that are already on Lot No. tracking only. The system will not allow to change the Item Tracking Code for an Item without clearing the Ledger Entries. Is there to effect this without losing Item History and if not is there a way of linking the old Item No. and the new Item No.?